Three-wheeled rear-steering scooter

ABSTRACT

A three wheeled scooter comprises a chassis having forward and aft ends with a front wheel non-pivotally mounted to the forward end and a pair of rear wheels coaxially mounted to the aft end. The chassis defines a longitudinal axis and includes a support assembly and a handle assembly extending upwardly from the support assembly. The rear wheels are configured to be angularly yawable relative to the longitudinal axis between a neutral position and a yawed position. Steering of the scooter is thereby effectuated by angular yawing of the rear wheels relative to the longitudinal axis such as by asymmetric loading of one of opposing sides of the support assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

(Not Applicable)

STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT

(Not Applicable)

BACKGROUND

The present invention relates generally to wheeled vehicles and, moreparticularly, to a uniquely configured three-wheeled, rear-steeringscooter having a single front wheel and a pair of smaller-diameter rearwheels wherein the scooter is specifically adapted to be steered by anoperator due to angular yawing of the rear wheels in response to lateralrolling or tilting of a chassis to which the rear wheels are pivotallymounted.

Scooters are well known in the prior art and are available in a widevariety of configurations with each configuration possessing certainadvantages that allow a rider or operator to perform certain maneuversthat cannot be performed with other scooter configurations. For example,U.S. Pat. No. 6,250,656 issued to Ibarra discloses a scooter having anelongated footboard supported at its rear by a pair of small diameterwheels and at its front end by a large diameter front wheel. The scooterincludes positive steering capability via a pivotable front wheel thatis steerable by an operator via handlebar assembly. The footboardincludes an upwardly angled flat portion located aft of the rear wheelsand which is oriented at an angle to allow upward pitching of thescooter in response to the operator stepping on the flat portion suchthat the operator may perform “wheelies”, and allowing the scooter tojump over objects.

U.S. Pat. No. 5,620,189 issued to Hinderhofer discloses a scooter havinga frame assembly which includes a footboard at a rear of the frameassembly and a large-diameter front wheel located at a front end of thescooter. The rear of the footboard is supported by at least oneunsteerable rear wheel preferably located below the footboard.Alternatively, the scooter may include a plurality of rear wheels whichmay be arranged in an in-line configuration which provide a plurality ofrolling surfaces to facilitate gliding movement over uneven terrain suchas stair steps or street curbs. Steering of the scooter is facilitatedby means of a handlebar assembly by which a rider may pivot the frontwheel and therefore steel the scooter in a conventional manner.

U.S. Pat. No. 6,739,606 issued to Rappaport discloses a dual-footboardscooter provided in a tricycle arrangement having a front wheel ofrelatively large diameter and being joined to a frame. The frame extendsrearwardly in a bifurcated arrangement to form two branches, each ofwhich is supported by a single rear wheel. Each of the branches includesa generally horizontally-oriented footboard supported at its rear end bythe rear wheel. An operator may rest one foot on one of the footboardswhile making pushing contact with the ground in order to propel thescooter forward. Steering of the scooter is effectuated by the frontwheel which is pivotable by means of a handlebar assembly for steeringthe scooter.

U.S. Pat. No. 6,220,612 issued to Beleski discloses a three-wheeledscooter configured as a “cambering vehicle” having a single steerablefront wheel and a pair of rear wheels disposed on separate trailingarms. Each of the trailing arms is articulably to a front column fromwhich the front wheel extends. Forward motion of the scooter isgenerated by the operator alternating shifting of weight fromside-to-side as the scooter travels a sinusoidal path produced by theoperator steering the front wheel left and right by means of a handlebarassembly. The simultaneous shifting of weight from one side to the otherin combination with the steering of the vehicle produces a series ofaccelerations under the principle of conservation of angular momentumwhich results in forward motion of the scooter.

The prior art includes additional alternative scooter configurations inaddition to the above described scooter arrangements. A majority of theprior art scooters facilitate directional control of the scooter bymeans of a pivotable front wheel which is coupled to a handlebarassembly by which the operator may steer the scooter. Furthermore, manyof the scooter arrangements of the prior art are configured such thatthe front and rear wheels are spaced a relatively large distance fromone another such that the scooter is incapable of performingshort-radius turns. Even further, many of the scooter arrangements ofthe prior art include conventional bicycle handlebars comprising a pairof laterally outwardly extending arm members which require gripping byboth of the rider's hands for effective control and steering of thescooter in a stabilized manner.

As may be appreciated, there exists a need in the art for a scooterproviding an operator or rider with the capability to execute turns ofvarying radii including relatively short-radius turns in order toincrease the range of maneuvers that may be performed. Furthermore,there exists a need in the art for a scooter that may be operated by therider in a standing position but which eliminates the need for steeringthe scooter by turning a handlebar using the rider's hands.

Additionally, there exists a need in the art for a scooter whichprovides a means for stabilizing or balancing the rider in order toallow adults as well as children to operate the scooter without the riskof injury as a result of falling from the scooter. Finally, there existsa need in the art for a scooter which is of simple construction, lowcost, reduced size and of relatively low weight in order to enhance thescooter's maneuverability and to facilitate transportation and storageof the scooter.

BRIEF SUMMARY

The present invention specifically addresses the above-described needsby providing a three-wheeled, rear-steering scooter having thecapability to execute turns of varying radii including relatively shortradius turns. The three-wheeled, rear-steering scooter comprises achassis having a relatively large diameter front wheel fixedly mountedat a forward end of the chassis and a pair of smaller diameter rearwheels pivotally-mounted at an aft end of the chassis. In oneembodiment, the scooter is configured to allow steering by angularyawing of the rear wheels relative to the chassis. Such angular yawingis effectuated by asymmetric loading of the chassis which causes lateralrolling of the chassis. The lateral rolling may be induced by unevenweighting of left and right sides of the chassis which, in turn, causesthe rear wheels to pivot or yaw for steering control of the scooter.

In its broadest sense, the scooter comprises the chassis, thenon-pivotable (i.e., non-steerable) front wheel mounted to the forwardend of the chassis and an angularly-yawable pair of rear wheels mountedto the aft end of the chassis. The chassis defines a longitudinal axisextending between the forward and aft ends. The chassis may comprise agenerally horizontally-oriented support assembly extending from theforward end to the aft end for supporting a rider or operator in astanding position.

Optionally, the scooter may include a handle assembly located forward ofthe support assembly and extending upwardly therefrom. The handleassembly may be configured as a single vertical member having a grippingpotion (i.e., a hand grip) for gripping by one of the rider's hands.Alternatively, the handle assembly may be configured as a pair oflateral members each having gripping portions similar to theconfiguration of conventional handlebars. Regardless of itsconfiguration, the handle assembly provides a means for stabilizing therider or operator of the scooter.

The rear wheels are preferably disposed laterally relative to oneanother and, as was mentioned above, are specifically configured to beangularly yawable relative to the longitudinal axis. In this regard, therear wheels are adapted to pivot or yaw between a neutral position and ayawed position. In the neutral position, the axis of the rear wheelsoriented perpendicularly relative to the longitudinal axis. In the yawedposition, the rear wheels are oriented in a non-perpendiculararrangement relative to the longitudinal axis. Direction control orsteering of the scooter is effectuated solely or primarily as a resultof angular yawing of the rear wheels between the neutral and yawedpositions.

The support assembly is preferably configured to laterally roll aboutthe longitudinal axis. Such lateral rolling may be effectuated byasymmetric loading of one of right and left sides of the supportassembly. The asymmetric loading may be induced by the rider applyingdownward pressure to the left or right side of the support assembly suchas by uneven weighting using the rider's feet. This asymmetric loadingand lateral rolling of the support assembly induces the angular yawingmotion of the rear wheels which causes the scooter to turn.

Preferably, the rear wheels are pivotally mounted to the supportassembly by means of a trunnion comprising a rear axle. In oneembodiment, the rear wheels are mounted on opposing ends of the axle.The trunnion is attached to the support assembly by means of a pivotshaft which extends upwardly from the rear axle. The pivot shaftinterconnects the rear axle to the support assembly. Biasing members maybe incorporated into the mounting of the rear axle to the supportassembly. The biasing member may provide a self-steering orself-stabilizing characteristic to the rear axle, as will be describedin greater detail below.

Ideally, the pivot shaft is oriented in an inclined manner relative tothe longitudinal axis. More specifically, the pivot shaft may have upperand lower ends and is inclined such that the lower end is locatedforward of the upper end. In this manner, the pivot shaft is orienteddownwardly along a direction from the aft end of the chassis toward theforward end. The downward inclination of the pivot shaft results inangular yawing of the rear wheels at the same time the support assemblyrolls laterally to the right or left. The lateral rolling motion of thesupport assembly is in proportion to the degree of angular yawing of therear wheel. The net effect of this combination of motions allows a riderto lean into a turn with greater yaw angles of the rear wheelscorresponding to greater amounts of lateral rolling motion of thesupport assembly.

For example, if the rider wishes to execute a right turn of the scooter,the rider asymmetrically loads the right side of the support assemblyresulting in the right side laterally rolling or pivoting downwardlyabout the longitudinal axis while the left side of the support assemblypivots upwardly. Simultaneously, the rear axle is caused to yawangularly such that the rear wheel on the right side of the longitudinalaxis moves forward while the rear wheel on the left side moves aft. Thisangular yawing causes a the scooter to be redirected toward the right(i.e., point toward the right) during forward movement of the scooter.

It is contemplated that the trunnion may be configured such that theyawing capability of the rear axle relative to the longitudinal axis isa half-angle of at least about 45°. However, the trunnion may beconfigured to allow yawing of the rear axle up to half-angles of lesseror greater amounts. A biasing member may optionally be included with thetrunnion and is operatively connectable to the trunnion. The biasingmember is preferably configured to bias the rear axis toward the neutralposition in order to provide a self-steering mechanism. In this manner,the rear axle is urged back toward a non-yawed position (i.e., neutralposition) following each turn.

The biasing member further provides a self-stabilizing mechanism for thescooter whereby the rear axle may better resist unwanted wobbling oroscillations in the support assembly when the scooter is traveling athigh speed. Even further, the biasing member provides a self-parkingfeature wherein the support assembly returns to a horizontal or levelorientation when the rider dismounts the scooter. The handle assemblywill also return to a vertical orientation when the rider dismounts thescooter or when the scooter is stationary.

Optionally, the scooter may include an articulated joint at the forwardend of the support or assembly. Alternatively, the articulated joint maybe positioned so as to interconnect the support assembly to the handleassembly. Regardless of its specific location on the chassis, thearticulated joint advantageously provides an alternative means forfacilitating the lateral rolling motion of the support assembly. Morespecifically, the articulated joint allows for lateral rolling motion ofthe support assembly upon which the rider stands in a direction oppositethat of the handle assembly. The articulated joint may provide analternative mode of propelling the scooter forward as a result oflateral rolling the support frame out-of-phase with the handle assemblyin a manner as will be described in greater detail below.

The scooter may optionally include a suspension system operativelycoupled to at least one of the front and rear wheels to absorb shockthat would otherwise be transmitted to the rider during travel overuneven terrain. More specifically, the suspension system is preferablyconfigured to allow for vertical deflection of the front and/or rearwheels relative to the chassis as may be desirable when encounteringgravel, cracks in pavement, or other natural or manmade obstacles.

BRIEF DESCRIPTION OF THE DRAWINGS

These as well as other features of the present invention will becomemore apparent upon reference to the drawings wherein:

FIG. 1 is a perspective view of a three-wheeled rear-steering scooterhaving a front wheel non-pivotally mounted to a forward end of thechassis assembly and a pair of rear wheels pivotally mounted to an aftend of the chassis;

FIG. 2 is a side view of the scooter of FIG. 1 illustrating a seat orperch extending laterally outwardly from the chassis assembly forsupporting an operator;

FIG. 2 a is an enlarged side view of the chassis assembly illustratingan inclined orientation of an axis about which the rear wheels pivot andwhich facilitates angular yawing of the rear wheels for steering of thescooter;

FIG. 2 b is an aft view of the rear wheels and illustrating theindependent pivotal mounting of each rear wheel and the coupling of therear wheels to facilitate their angular yawing in unison;

FIG. 3 is a rear view of the scooter illustrating a trunnion comprisinga rear axle and a pivot shaft interconnecting the rear axle to thechassis;

FIG. 4 is a side view of the scooter illustrating a rider inducing alateral rolling motion to the chassis to effectuate angular yawing ofthe rear wheels;

FIG. 4 a is a top view of the scooter taken along line 4 a of FIG. 4 andillustrating the yaw angle of the rear wheels relative to thelongitudinal axis of the scooter during a turn;

FIG. 5 is a side view of the scooter in an embodiment having a strutmember extending downwardly from the handle assembly;

FIG. 6 is a side view of a vertically oriented handle assemblyconfigured for stabilizing an operator of the scooter as compared to thehandlebar-like arrangement illustrated in FIGS. 1, 2 and 4; and

FIG. 7 is a side view of the scooter in an alternative embodimentwherein the chassis includes an articulated joint to allow lateralrolling motion of a support assembly relative to a front wheel of thescooter.

DETAILED DESCRIPTION

Referring now to the drawings wherein the various showings are forpurposes of illustrating preferred embodiments of the present inventionand not for purposes of limiting the same, shown in the figures is athree-wheeled rear-steering scooter 10. In its broadest sense, thescooter 10 comprises a chassis 18 having a front wheel 44 and a pair ofrear wheels 56 pivotally mounted to the chassis 18 so as to be angularlyyawable to allow for steering of the scooter 10. As can be seen in FIGS.1 and 2, the chassis 18 has a forward end 12 and an aft end 14 anddefining a longitudinal axis A extending from the forward end 12 to theaft end 14. The chassis 18 may include a generally horizontally-orientedsupport assembly 24 to which the rear wheels 56 may be mounted. Thesupport assembly 24 may comprise a foot support 26 upon which anoperator 16 or rider of the scooter 10 may stand such as when riding thescooter 10.

The front wheel 44 is non-pivotally (i.e., non-steerably) mounted at theforward end 12 of the chassis 18. The chassis 18 may further include anoptional handle assembly 32 which is preferably located forward of thesupport assembly 24 and which extends upwardly from the support assembly24 as shown in FIGS. 1-2 and 4-7. In one embodiment, the handle assembly32 is rigidly connected by suitable means (e.g., mechanical fasteners,welding, etc.) to the support assembly 24. However, the support assembly24 and handle assembly 32 may be formed as a unitary structure.

Alternatively, the handle assembly 32 and support assembly 24 may beinterconnected by an articulated joint 30 to allow relative lateralrolling motion therebetween, as will be described in greater detailbelow. The handle assembly 32 is configured to provide a means by whichthe rider or operator 16 may be stabilized or balanced in a standingposition while riding the scooter 10. For embodiments where the supportassembly 24 and handle assembly 32 are rigidly interconnected, thehandle assembly 32 also provides a means for steering the scooter 10 asa result of the rider inducing lateral or sideways motion of the handleassembly 32. Because of the rigid connection between the handle assembly32 and the support assembly 24, lateral rolling motion of the handleassembly 32 is transmitted to the support assembly 24. The resultantlateral rolling motion of the support assembly 24 induces the angularyawing motion of the rear wheels 56 by which the scooter 10 is steered,as will be described in greater detail below.

As best seen in FIGS. 1 and 2 b, the rear wheels 56 are mounted on theaft end 14 of the support assembly 24 such that the rear wheels 56 aredisposed laterally relative to one another. Mounting of the rear wheels56 to the support assembly 24 may be facilitated with a trunnion 58which may comprise a rear axle 60 having a pivot shaft 62 extendingoutwardly therefrom such as from a mid-point of the rear axle 60. Asshown in FIGS. 1 and 3, the rear wheels 56 rotate about the rear wheelaxes D and are specifically adapted to be angularly yawable relate tothe longitudinal axis A between a neutral position 68 (i.e., shown inFIG. 1) and a yawed position 70 (shown in FIG. 4 a). Importantly,because the front wheel 44 is fixedly secured to the chassis 18 (i.e.,non-pivotably mounted), the steering of the scooter 10 is effectuatedprimarily or solely by angular yawing or pivoting of the rear wheels 56relative to the longitudinal axis A.

As can be seen in FIG. 4 a, the support assembly 24 is configured toroll laterally about the longitudinal axis A. In one embodiment of thescooter 10, the lateral rolling motion of the support assembly 24induces the rear wheels 56 to angularly yaw which comprises the steeringmechanism for the scooter 10. For example, an operator 16 may initiate aturn of the scooter 10 by asymmetrically loading one of opposing rightand left sides of the support assembly 24 and, due to the orientation ofthe pivot axis B at pivot axis angle θ, causes the rear wheels 56 to yawin a counterclockwise direction relative to the longitudinal axis A asbest seen in FIG. 4 a. More specifically, FIG. 4 a illustrates thecounterclockwise yawing of the rear wheels 56 relative to thelongitudinal axis A as a result of weighting or loading of the rightside of the support assembly 24.

Referring briefly to FIG. 2, shown is the operator 16 standing on thefoot support 26 with the right leg bearing most or all of the operator'sweight. This asymmetric loading on the right side of the supportassembly 24 causes the lateral rolling movement which induces theangular yawing movement of the rear wheels 56 to the position shown inFIG. 4 a. Alternatively, loading of the left side of the supportassembly 24 would have the reverse effect of inducing clockwise yawingmotion of the rear wheels 56 relative to the longitudinal axis A inorder to initiate a left turn. As may be appreciated, the operator 16may directionally control the scooter 10 during forward travel byvarying the asymmetric loading on the right and left sides of thesupport assembly 24. The asymmetric loading may be facilitated by merelyshifting the operator's weight to the left or right leg.

In one embodiment, such as that shown in FIG. 4 a, the trunnion 58 uponwhich the rear wheels 56 are mounted is preferably adapted to provideyawing capability to the rear axle 60 relative to the longitudinal axisA at a half angle of up to about 45°. However, it should be noted thatthe trunnion 58 may be configured to provide any degree of angularyawing capability. As can be seen in FIGS. 1 and 3, the rear wheels 56are preferably mounted on opposing ends of the rear axle 60.

In a preferred embodiment, the pivot shaft 62 is disposed in anon-vertical and non-horizontal orientation such that asymmetric loadingof the support assembly 24 causes the angular yawing of the rear wheels56. Even more preferably, the pivot shaft 62 is preferably oriented atpivot axis angle θ such that lateral rolling of the support assembly 24causes the rear wheel 56 on that side to move forward while the rearwheel 56 on the opposing side moves aft. Such an arrangement allows theoperator 16 to lean into the turn at progressively greater amounts inproportion to the extent of the lateral rolling motion.

Advantageously, the ability to lean into the turns allows the operator16 to counteract the effects of centrifugal force which tend to throwthe rider toward the outside of the turning radius. Although the pivotshaft 62 is preferably oriented to allow a rider to lean into the turn(i.e., facilitates movement of the rider's center of gravity toward theinside of the turn radius), it is contemplated that the pivot shaft 62may be oriented in a variety of other arrangements. For example, thepivot shaft 62 may be oriented such that asymmetric loading of one sideof the support assembly 24 results in angular yawing of the rear wheels56 in an opposite direction.

However, as best seen in FIGS. 1, 2 and 6, the preferred arrangement issuch that the pivot axis B is inclined at pivot axis angle θ relative tothe longitudinal axis A such that the pivot axis B is orienteddownwardly along a direction from the aft end 14 toward the forward end12 of the chassis 18. More specifically, the pivot shaft 62 has upperand lower ends and is inclined such that the lower end of the pivotshaft 62 is located forward of the upper end of the pivot shaft 62.

As was earlier mentioned, when the support assembly 24 is laterallyrolled to the left or to the right, the inclined pivot shaft 62 allowsfor mechanical steering of the rear wheels 56 in yaw at a directionopposite the direction of intended turning of the scooter 10. Forexample, if the operator 16 wishes to execute a right turn of thescooter 10, the operator 16 may asymmetrically load the right side ofthe support assembly 24 which causes laterally downward rolling of thesupport assembly 24. This laterally downward rolling of the supportassembly 24 causes the rear wheels 56 to turn in an opposite direction.In this manner, the operator 16, by exerting uneven weighting of thefoot support 26, induces lateral rolling thereof which, in turn,effectuates angular yawing or turning of the rear wheels 56. The greaterthe degree of asymmetric loading of the support assembly 24, the greaterthe degree of angular yawing (i.e., the smaller the turn radius).

As can be seen in the figures, the handle assembly 32 is located forwardof and extends upwardly from the support assembly 24 in a generallyvertical orientation. In one embodiment shown in FIG. 6, the handleassembly 32 includes a vertical arm member 36 which extends upwardlyfrom a pair of down tubes 22 or forks to which the front wheel 44 ismounted. The vertical arm member 36 is configured to be grasped orgripped by the operator 16 for stabilizing and/or balance while ridingthe scooter 10. Advantageously, the handle assembly 32 also facilitateslateral rolling of the support assembly 24 due to its rigid connectionthereto. In this manner, the operator 16 can initiate steering at thehandle assembly 32 by a combination of asymmetric loading of the supportassembly 24 and lateral rolling of the handle assembly 32 in order toeffectuate quicker rates of yawing of the rear wheels 56.

Referring still to FIG. 6, the vertical arm member 36 of the handleassembly 32 may be fitted with a ergonomically shaped gripping portion38 or a hand grip which the operator 16 may grasp. The chassis 18 mayfurther include an arch-shaped strut member 28 extending from the handleassembly 32. The strut member 28 is preferably aligned with the frontwheel 44 and is connected to the foot support 26 at its lower end. Thestrut member 28 may add to the overall structural rigidity, torsionalstiffness and general strength of the chassis 18. The added stiffnessand strength may be desirable during the performance of certainmaneuvers or when operating the scooter 10 on challenging terrain.

The strut member 28 is preferably configured such that when riding thescooter 10, the operator's legs straddle the strut member 28. However,the strut member 28 may be altogether eliminated and the chassis 18provided in the arrangement shown in FIGS. 1 and 2. In embodimentswherein the strut member 28 is omitted, the support assembly 24 andhandle assembly 32 are preferably sized to collectively providesufficient strength and rigidity to the chassis 18.

Referring to FIGS. 1, 2 and 3, the scooter 10 may further include abiasing mechanism or biasing members 54 operatively connected to thetrunnion 58 and configured to bias the rear axle 60 toward the neutralposition 68. As was earlier mentioned, when the rear axle 60 is in theneutral position 68, the rear axle 60 is oriented generallyperpendicularly relative to the longitudinal axis A of the chassis 18.If included, the biasing members 54 preferably induces a return of therear wheels 56 from a yawed position 70 as shown in FIG. 4 a to thenon-yawed or neutral position 68 as shown in FIG. 1. In this regard, thebiasing members 54 resists the lateral rolling or tilt of the supportassembly 24 and induces a return of the support assembly 24 to anon-rolled position which provides a desirable stabilizingcharacteristic to the scooter 10.

Additionally, the biasing members 54 is preferably configured to providea progressively higher degree of stiffness or biasing force atprogressively greater yaw angles of the rear wheels 56. Theprogressively higher stiffness of the biasing members 54 also preventsthe support platform from laterally oscillating or wobbling (i.e., fromside-to-side) which is important when traveling at high speed. A furtherbenefit provided by the biasing members 54 is a self-standingcharacteristic when the scooter 10 is stationary or parked such that thehandle assembly 32 and front wheel 44 are maintained in a verticalorientation. Overall, the biasing members 54 provides stability to thescooter 10 at low speed as well as at high speed by resisting laterallyrolling motion of the support assembly 24.

The biasing members 54 may be configured in a variety of arrangementsincluding, but not limited to, a rubber element or member securedbetween the support assembly 24 and the trunnion 58 in order to resistrelative motion between the rear axle 60 and the support assembly 24.Alternatively, a spring 50 or pair of springs may be inserted betweenthe rear axle 60 and the support assembly 24 in order to resist lateralrolling motion. A spring dampener 52 may be further included with thebiasing members 54 in order to reduce the spring 50 rate of the biasingmembers 54 to further stabilize the scooter 10.

In an alternative embodiment, FIG. 2 b illustrates individual mountingof each of the rear wheels 56 by means of a pair of generallyvertically-oriented spindles 64. Each of the spindles 64 defines a pivotaxis B about which the rear wheels 56 pivot. As can be seen in FIG. 2 b,the pair of rear wheels 56 may be interconnected by means of a linkage66 or tie rod. In this manner, the rear wheels 56 are mechanicallycoupled to one another such that the rear wheels 56 may yaw in unisonabout their corresponding pivot axes B.

FIG. 2 b further illustrates a control arm secured to each of thespindles 64 for interconnecting the rear wheels 56 by means of linkage66 or tie rod. At least one of the spindles 64 may include a steeringarm (not shown) attached to one of the rear wheels 56. Pivoting motionprovided to one of the rear wheels 56 by the control arm is, in turn,transferred to the other one of the rear wheels 56 by means of thelinkage 66. Steering of the scooter 10 may then be effectuated by afoot-actuated or hand-actuated steering mechanism such as a lever (notshown) which induces pivoting motion at the control arm and, which isthen transferred to the rear wheels 56.

Referring briefly to FIG. 1, the scooter 10 may further include asuspension system 20 which is operatively coupled to at least one of thefront and rear wheels 44, 56. The suspension system 20 is preferablyadapted to allow for vertical deflection of the front 44 and/or rearwheels 56 relative to the chassis 18 such as may occur when riding uponuneven terrain or when encountering small obstacles such as gravel,cracks in pavement or expansion joints in sidewalks. The suspensionsystem 20 may include a pair of spring mechanisms such as shockabsorbers which may optionally further include a dampener 52 in order tocontrol the rebound rate and dampen oscillations of the springmechanisms.

As shown in FIG. 1, the suspension system 20 may comprise a shockabsorber type of assembly incorporated into each of the down tubes 22 onopposing sides of the front wheel 44. Each of the shock absorbers mayterminate at a flange 48 located on each of the down tubes 22. Theflange 48 supports hub 46 of the front wheel 44 with the front wheel 44being rotatable about front wheel axis C. Alternatively, the suspensionsystem 20 may be configured in other arrangements such as, for example,a spring 50 and/or dampener 52 unit incorporated into the vertical armmember 36 located directly above the down tubes 22. It is furthercontemplated that the rear wheels 56 may include a suspension system 20between the support assembly 24 and the trunnion 58, for example, inorder to allow for vertical deflection of the rear wheels 56 relative tothe chassis 18 such as may occur when the rear wheels 56 encounteruneven terrain.

Referring to FIG. 4, shown is the scooter 10 with the handle assembly 32wherein the operator 16 may grasp at least one or both of the lateralarm members 34 for stabilization during straight and level riding aswell as during performance of turning maneuvers. Each of the arm members34 may be provided with a gripping portion 38 in order to facilitatesecure grasping by the operator's hands.

Although handle assembly 32 appears similar to conventional handlebars,it should be emphasized that the front wheel 44 is non-pivotally securedto the chassis 18 and therefore provides no steering capability asconventionally exists in a bicycle. In this regard, steering of thescooter 10 is effectuated primarily and solely by angular yawing of therear wheels 56 in response to lateral rolling of the support assembly 24as a result of weight shifting and/or as a result of lateral motion ofthe handle assembly 32 from side-to-side. The handle assembly 32 arepreferably located at a height suitable for convenient grasping by theoperator 16 in the standing or sitting position. It is contemplated thata height adjustment feature may be included in the handle assembly 32 inorder to accommodate riders of different sizes. Furthermore, the lateralextending arm members 34 may be provided in an interchangeableconfiguration in order to allow mounting of handle assemblies ofdiffering widths, shapes and/or angular orientation.

Referring briefly to FIGS. 1 and 2, the scooter 10 may further include aseat or perch 72 supported by a perch post 74 which may extend laterallyaftwardly from an upper portion of the handle assembly 32. The perch 72is preferably mounted on the perch post 74 at a height which is suitablefor straddling or mounting by the operator 16 such that the rider'sknees are slightly bent. Optionally, the perch 72 may be configured tobe height-adjustable to suit operators 16 of different height.Furthermore, the perch 72 is preferably adapted to be pivotallyconnected to the handle assembly 32 such that the perch post 74 may befolded generally parallel to the handle assembly 32. When folded theperch post 74 minimizes the total volume occupied by the scooter 10 tofacilitate shipping and storage of the scooter 10.

To facilitate pivoting of the perch post 74, the scooter 10 may furtherinclude a slotted brace 76 having a slot with a detent at one endthereof and which is configured to engage a pin mounted to the supportassembly 24, as shown in FIG. 2. In this manner, upward pivoting of theperch post 74 is facilitated by first disengaging the detent from thepin such that the pin may slide through the slot as the perch post 74 ispivoted upwardly.

Referring briefly to FIG. 7, in a further embodiment of the scooter 10,the chassis 18 is shown having an articulated joint 30 interposedbetween the support assembly 24 and handle assembly 32 at a forwardlower end of the chassis 18. The articulated joint 30 is configured totorsionally couple the horizontally oriented support assembly 24 withthe vertically oriented handle assembly 32. In this regard, thearticulated joint 30 is configured to allow for lateral rolling motionof the support assembly 24 in a direction opposite that of the handleassembly 32.

The articulated joint 30 provides a means by which the operator 16 maypropel the bicycle skateboard by laterally rolling the foot support 26(i.e., due to asymmetric loading thereof) out-of-phase with the handleassembly 32. Propulsive force may thereby be generated which thentranslates into forward motion of the scooter 10. The articulated joint30 may further include a biasing means such as a coil spring 50 and/ordampening means in order to bias the support assembly 24 and handleassembly 32 into neutral alignment and which facilitates theout-of-phase motion of the support assembly 24 relative to the handleassembly 32. Such an arrangement also provides a self-steeringcharacteristic to the scooter 10 as well as a self-standing featureduring periods of non-use of the scooter 10. The biasing means furtherprovides rolling resistance to the support assembly 24 relative to thehandle assembly 32 and thereby stabilize the scooter 10 at low speeds.

Referring still to FIG. 7, the perch 72 may be supported in analternative arrangement wherein the perch post 74 extends verticallyupwardly from the foot support 26 in order to allow for seated operationof the scooter 10. A pair of braces 76 may extend upwardly from the footsupport 26 to increase the load-carrying capability of the perch post 74under the weight of the operator 16 seated on the perch 72. The footsupport 26 is preferably configured to provide sufficient area forplacement of the operator's feet when seated on the perch 72.

Referring briefly to FIG. 2, the scooter 10 may optionally include amotor 82 drivingly coupled to at least one of the front and rear wheels44, 56. The motor 82 is configured to impart rotational motion to thefront and/or rear wheels 44, 56 in order to propel the scooter 10. Themotor 82 may be configured as an electric motor 82 and may beoperatively coupled to the rear wheels 56 such as by means of a motorshaft connected to the rear axle 60. Power for the motor 82 may beprovided by means of a power source 84 such as a battery which, inconjunction with the motor 82, may be mounted below the foot support 26such as that shown in FIG. 2. Preferably, the motor 82 and/or powersource 84 are mounted in such a manner so as to provide sufficientground clearance to accommodate lateral rolling motion of the supportassembly 24 during steering of the scooter 10.

Regulation of the motor 82 may be facilitated through the use of athrottle 40 which may be mounted on the handle assembly 32 as shown inFIGS. 2, 4, and 5. Braking or slowing of the scooter 10 may befacilitated through the use of a brake mechanism such as a disc brake orrim brakes operated via a brake lever 42 also mounted on at least one ofopposing lateral arm members 34 as shown in FIGS. 2, 4 and 5.

Referring to FIGS. 1-4, the general configuration of the chassis 18includes the horizontally-oriented support assembly 24 which forms thesupport surface upon which the operator 16 may stand and to which therear wheels 56 are pivotally mounted. In an embodiment shown in FIG. 3,the foot support 26 may be comprised of an arrangement of structuralelements such as tubular members which are configured to providesufficient surface area for supporting both of the rider's feet.

Regarding the geometric relationship of the various components of thescooter 10, the front wheel 44 is preferably a pneumatic wheel ofrelatively large diameter (e.g., 12 inch-28 inch) and preferably havinga tire tread of a width generally less than about 2 inches althoughwider tires are contemplated. The cross sectional geometry of the tiretread itself is preferably radiused to facilitate lateral rolling motionof the front wheel 44. The diameter of the front wheel 44 is preferablybetween about 6-10 times the diameter of the rear wheels 56. The rearwheels 56 each preferably have a width generally equal to the diameterof the rear wheels 56 although various other width/diameter ratios arecontemplated. The rear wheels 56 also preferably have a generally flator planar tread surface in order to maximize lateral traction duringturning.

As was indicated earlier, steering of the scooter 10 is facilitated byangular yawing of the rear wheels 56 in response to asymmetric loadingor weighting of the support assembly 24 by the operator 16. By exertinguneven loading on the foot support 26, lateral rolling motion of thesupport assembly 24 and handle assembly 32 to which the front wheel 44is connected results in angular yawing or turning of the rear wheels 56.The greater the amount of lateral rolling of the chassis 18 or supportassembly 24, the greater the angular yawing movement at the rear wheels56 which results in a relatively tighter turning radius of the scooter10.

Because the collective area of the contact patch of the rear wheels 56are greater than the contact patch at the front wheel 44, steering ofthe scooter 10 is achieved primarily as a result of angular yawing orturning displacement of the rear wheels 56 in relation to thelongitudinal axis A. Traction of the rear wheels 56 may be maximized byoptimizing the degree of compliancy of the rear wheels 56 relative tothe amount of lateral roll of the support assembly 24. In this manner,the rear wheels 56 can remain in contact with the ground during steeringof the scooter 10 regardless of the yaw angle of the rear wheels 56.

The scooter 10 may further be provided with additional accessories orfeatures. For example, as shown in FIGS. 1 and 2, a fender 80 may beincluded for preventing contact of the operator 16 with the front wheel44. As can be seen, the fender 80 may be mounted to the down tubes 22 ofthe handle assembly 32. Likewise, small fenders 80 may be provided overeach of the rear wheels 56 in order to prevent inadvertent contact withthe rider's foot. Wheelie bars may optionally be included with thescooter 10 whereby the wheelie bars may be extended aftwardly from therear of the support assembly 24 in order to prevent over-rotation orflipping of the scooter 10. Foot pegs may optionally be disposed at orbelow the front axle of the front wheel 44. Likewise, floorboards,baskets, bags and/or training wheels may further be included with thescooter 10. In addition, lighting fixtures such as forward headlightsand aft tail lights may be included with the scooter 10 as a safetyfeature or to enable operation during reduced visibility conditions.

In operation, the scooter 10 may be propelled in a forward direction bya variety of different modes including the operator 16 simply pushing inan aftward direction such as with the operator's foot. As was earlierdescribed, the scooter 10 may further be propelled in a forwarddirection by laterally rolling the front wheel 44 out-of-phase withlateral rolling of the support assembly 24. Energy generated during suchout-of-phase motion facilitates forward propulsion of the scooter 10.Forward propulsion of the scooter 10 may further be provided by anelectric motor 82 imparting rotational motion to at least one of thefront and/or rear wheels 44, 56. Regulation of the motor 82 may befacilitated by a throttle 40 which may be mounted to the handle assembly32 as shown in FIG. 5. Slowing or stopping of the scooter 10 may befacilitated by a brake mechanism which may be regulated via a brakelever 42 which may be mounted on the handle assembly 32 as shown in FIG.5.

The above description is given by way of example and not limitation.Given the above disclosure, one skilled in the art could devisevariations that are within the scope and spirit of the inventiondisclosed herein. Furthermore, the various features of the embodimentsdisclosed herein can be used alone or in varying combinations with eachother and are not intended to be limited to the specific combinationsdescribed herein. Thus, the scope of the claims is not to be limited bythe illustrated embodiments.

What is claimed is:
 1. A three-wheeled scooter, comprising; a chassishaving forward and aft ends and defining a longitudinal axis, thechassis including a support assembly; a front wheel non-pivotallymounted to the forward end; and a pair of rear wheels coaxially mountedto the aft end and being yawable relative to the longitudinal axisbetween a neutral position and a yawed position; wherein: steering ofthe scooter is effectuated by angular yawing of the rear wheels relativeto the longitudinal axis.
 2. The scooter of claim 1 wherein the supportassembly is configured such that lateral rolling thereof effectuatesangular yawing of the rear wheels.
 3. The scooter of claim 1 furtherincluding a handle assembly rigidly connected to the support assemblysuch that lateral movement of the handle assembly facilitates yawing ofthe rear wheels.
 4. The scooter of claim 1 further including: a trunnioncomprising a rear axle and a pivot shaft extending outwardly from therear axle, the pivot shaft pivotally interconnecting the rear axle tothe support assembly; wherein: the rear wheels are mounted on opposingends of the rear axle; the pivot shaft being oriented such that pivotingof the rear axle thereabout causes yawing of the rear wheels relative tothe longitudinal axis.
 5. The scooter of claim 4 wherein the trunnion isconfigured such that the yawing capability of the rear axle relative tothe longitudinal axis is a half-angle of at least about 45 degrees. 6.The scooter of claim 4 wherein the pivot shaft defines a pivot axisbeing inclined relative to the longitudinal axis.
 7. The scooter ofclaim 6 wherein the pivot axis is oriented downwardly along a directionfrom the aft end toward the forward end.
 8. The scooter of claim 4further including a biasing member operatively connected to the trunnionand being configured to bias the rear axle toward the neutral position.9. The scooter of claim 6 wherein: the chassis includes a handleassembly and having an articulated joint interconnecting the supportassembly to the handle assembly; the articulated joint being configuredto allow lateral rolling of the support assembly relative to the handleassembly.
 10. The scooter of claim 1 wherein: each of the rear wheels isindependently pivotally mounted to the support assembly; the rear wheelsbeing mechanically coupled to one another to angularly yaw in unison.11. The scooter of claim 10 further including: a pair of spindles and alinkage; wherein: each one of the spindles is configured to pivotallymount a corresponding one of the rear wheels to the support assembly;the linkage being configured to mechanically couple the rear wheels. 12.The scooter of claim 1 wherein the front wheel diameter is between aboutsix to ten times the rear wheel diameter.
 13. The scooter of claim 1wherein the support assembly includes a foot support for supporting anoperator standing thereupon.
 14. The scooter of claim 1 wherein thechassis further includes a perch portion extending laterally outwardlyfrom the chassis and being configured to support an operator sittingthereupon.
 15. The scooter of claim 14 wherein the perch portion isconfigured to be pivotally foldable generally parallel to the handleassembly.
 16. The scooter of claim 1 further including a motor drivinglycoupled to at least one of the front and rear wheels and beingconfigured to impart rotational motion thereto for propelling thescooter.
 17. The scooter of claim 1 further including a suspensionsystem operatively coupled to at least one of the front and rear wheelsand being configured to allow for vertical deflection thereof relativeto the chassis.
 18. The scooter of claim 1 wherein the chassis includesa handle assembly located forward of and extending upwardly from thesupport assembly and having a vertical arm member for gripping by anoperator.
 19. The scooter of claim 18 wherein the handle assemblyfurther includes a pair of opposing lateral arm members extendingoutwardly from the vertical arm member for gripping by the operator.